Much as I hesitate to disagree with Matthew, when he says "As I said above,
ontology is about the things in the world, not how we talk about them", I do
disagree. (01)
The problem of defining an ontology is surely one of defining the categories
(words/signs) of things (in the world) that we want to distinguish, and of
identifying the properties and range of property values that characterise
those things. A good ontology is one where, if there are a set of distinct
categories, a thing will be in exactly one category, and will have the
properties and property values required. (Up to this point, I doubt that we
disagree). (02)
In practice, in day-to-day life, there is agreement about many observable
categories and their properties. The problems come when there are different
categorizations of observables (such as colour terms) or where category is
inferred from the observables - for example, the categorization as something
as a bungalow, where the observables are a building, its windows and doors
etc. and knowledge is then used to infer bungalow. [This is complicated by
the need to assess the competence of the observer - does he know the
difference between a shovel and a spade?] (03)
I would therefore prefer that an ontology is the result of a dialectic
between an objective physical world, and a subjective, human constructed
vocabulary. The development of the vocabulary, in terms of scope and
precision, involves reassessment of the observable world, both as to the
adequacy and completeness of the observables that we count as the properties
of the category, and to the exactitude and certainty of the observables. (04)
The claim that a particular ontology is an objective model of the world is
essentially a claim that the dialectic has converged to the point that the
category are stable, and the list of essential properties agreed. It is
objective in the sense that any competent member of the linguistic community
will classify things in the ontology in the same way, and identify the same
properties in the same way. Further, a translation for another linguistic
community is likely to be comprehensible, even if they do not agree with the
categorization (think, for example, of categories of family relationships,
and how they would be treated by tribal societies not based on the nuclear
family). (05)
The problem comes when the ontology contains categories which are inferred
from the observables or defined by convention. For example, "a major fire",
"an accident", "a riot", "a medical specialist", "a qualified alternative
therapist". (06)
Thus, while I would agree that there are some objective models, such as the
chemical elements, and convention based models with objective properties,
such as units of measure, there are also non-objective models, such as the
categories in a Dewey Decimal System, or the categories of document that
company procedures recognise. In practice, much of what those of us in
business are interested in is the non-objective, business categories. In
this case, the basic categories should be exactly the labels for alternative
paths in a business process. To these will be added the categories that
support the heuristics of the particular community, either subdividing a
single category into sub-categories which support local linguistic
conventions (for example, Waterloo station is a single category from the
fares point of view, but two different stations when you want to get a
train) or the development of meta-categories (super classes). (07)
Consequently, saying an ontology is either about things the world OR about
how we talk about them is to make a false dichotomy. (08)
Sean Barker
Bristol (09)
From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx
[mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Matthew West
Sent: 30 October 2009 08:35
To: '[ontolog-forum] '
Subject: Re: [ontolog-forum] Just What Is an Ontology, Anyway? (010)
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But then how do we account for the diverse viewpoints going into the system
from multiple users? We all agree that each user has a unique ontology of
her personal world. We know that subjectivity gets squeezed into the
tightest databases with the strictest controls. (015)
MW: You can't. And in fact the problem really is just how do you impose
sufficiently strict controls such that the range of meaning is sufficiently
small that sufficiently accurate communication is possible. (016)
You must. As John Sowa is fond of saying, people play language games. (017)
MW: But computers don't. (018)
Those games are more complicated than we can decipher from signs alone. So
one enterprise level purpose of each subjective personal ontology is to
"correct" the personal viewpoint, projecting it back into the enterprise
ontology. (019)
MW: This is essentially the process of agreeing the enterprise ontology, or
aligning with it. (020)
But note that if you project the disjunction of all personal ontologies to
make up the enterprise ontology, you have to match common items shared among
personal ontologies. (021)
MW: I don't know anyone who would do it like that. Much more likely is that
a few people determine the enterprise ontology, and then others are left
with aligning their own viewpoint with it. (022)
For example, probably most or all normal English speakers think of fluids in
one way, solids in another and gases in a third. The English language
reflects the way we talk about the things belonging to these different
classes. (023)
MW: One has to be very careful about this. Language includes lots of old
ways of thinking about things that are not accurate. Ontology is about
modeling how things are in the world, not how we talk about them. (024)
So there is clearly a linguistic common ontology of objects and classes that
constitutes everyday usage. (025)
MW: No there is not, because with everyday language you can express any of
the ontologies you might find. Words have such a variety of usages, that it
can be difficult to accurately determine the meaning of words out o f
context, and sometimes even in context. (026)
That can be part of the enterprise ontology. But its part of EVERY language
competent ontology. (027)
MW: I've no idea what that might be. As I said above, ontology is about the
things in the world, not how we talk about them. (028)
So the enterprise ontology also includes things specific to the objects
about which that enterprise is concerned. (029)
Leading to the conclusion that the enterprise ontology will have to be
multilayered, scalloped like a 50's hot rod into component ontologies for
each viewpoint and each group of viewpoints. (030)
MW: Well yes you can do that (maybe), but at prohibitive expense because of
the interfaces between vewpoints, so I doubt if anyone will. This is back to
why a meeting of a French, Italian, German and Spanish people will conduct
business in English. (031)
Regards (032)
Matthew West
Information Junction
Tel: +44 560 302 3685
Mobile: +44 750 3385279
matthew.west@xxxxxxxxxxxxxxxxxxxxxxxxx
http://www.informationjunction.co.uk/
http://www.matthew-west.org.uk/ (033)
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